CERN, the European Organisation for Nuclear Research, has announced that the world’s most powerful particle accelerator is about to start up again and enter into a second phase of collisions in May.
After two years out-of-operation, the Large Hadron Collider (LHC) has been updated and is now ready to run at up to double the energy than it used previously, allowing physicists to extend the search for new particles and to check previously untestable theories.
In early 2013, after three years of running, the LHC was shut down for planned maintenance. Hundreds of engineers and technicians spent two years repairing and strengthening the accelerator in preparation for the next stage of its operation running at a much higher energy.
Based at CERN's facility near Geneva in Switzerland, the LHC allows scientists to reproduce the conditions that existed within a billionth of a second after the Big Bang, by colliding beams of high-energy protons close to the speed of light.
The machine consists of a 27-kilometre ring of superconducting magnets with a number of accelerating structures to boost the energy of the particles along the way. Inside the accelerator, two high-energy particle beams travel at close to the speed of light before they are made to collide.
According to CERN, the LHC is now almost cooled to its nominal operating temperature of -271°C. All teams are currently at work to get the LHC back online and carry out all the requested tests before circulating proton beams again later this month.
The energy of collisions in the LHC in 2015 will be 13 TeV (or 6.5 TeV per beam) compared to 8 TeV (4 TeV per beam) in 2012. The beams will also be narrower than before, as the width of the beam decreases with increasing energy. More tightly focused beams will allow for more interactions and collisions for the experiments to study
‘After the huge amount of work done over the last two years, the LHC is almost like a new machine,’ said CERN’s director for Accelerators and Technology, Frédérick Bordry. ‘Restarting this extraordinary accelerator is far from routine. Nevertheless, I’m confident that we will be on schedule to provide collisions to the LHC experiments by May 2015.’